I finally finished the active probe project!

Tell us what your doing from day to day. Post your daily notes here about any radio projects that you are working on.
User avatar
MN785
Donor
Donor
Posts: 25
Joined: October 12th, 2021, 7:18 pm
Age: 41

I finally finished the active probe project!

#408583

Post by MN785 »

I finally made an active probe so I can poke around inside radios without my old 10x probe loading down the circuits (especially the SSB frequency alignment on the DX2547 :angry-banghead: ). I tried this once before and it didn't work well, but now that I have dry film and can make decent PCB traces, it worked great! The probe is based on the poor man's active probe schematic by David Jewsbury, except I added an amplifier after the fet so it has a unity gain. I also added a low pass filter because I don't intend to use this for anything but CB radios, but the board picture was taken before that was added back when I had the filter spot by the SMA connector jumpered. I stuffed it into a chunk of copper tubing with caps and sealed it with foil tape. The tip is capacitively coupled to the FET using the board as a capacitor and the input capacitance is about 1pF :)
[Please login or register to view this link]

[Please login or register to view this link]

[Please login or register to view this link]







Donate to CBRT